نتایج جستجو برای: ionization effects
تعداد نتایج: 1578400 فیلتر نتایج به سال:
We study the interplay between Auger effects and ionization processes in the limit of strong electronic confinement in core/shell CdSe/ZnS semiconductor nanocrystal quantum dots. Spectrally resolved fluorescence decay measurements reveal a monotonic increase of the photoluminescence decay rate on excitation density. Our results suggest that Auger recombination accelerates ionization processes t...
This work presents density, spectroscopic temperature, and shockwave measurements of laser induced breakdown plasma in atmospheric air by subthreshold intensity 5.5 109 W /cm2 193 nm laser radiation. Using molecular spectroscopy and two-wavelength interferometry, it is shown that substantial ionization 1016 cm−3 occurs that is not predicted by collisional cascade CC breakdown theory. While the ...
We present results of our simulations of the ionization of a hydrogen atom excited to a Rydberg wave packet in the presence of external parallel electric and magnetic fields. This is an example of an open, quantum system whose classical counterpart has been shown to display chaos in the time domain. Within the framework of classical mechanics, electrons escape through chaos induced pulse trains...
calix(6)arene hydroxamic acids (iii) are synthesised for the first time by reactingcalix(6)arene acid chloride(ii) with substituted hydroxylamines at low temperature in the presence ofsodium bicarbonate. the p-carboxycalix(6)arene(i) is obtained by an acid catalysed condensationreaction of p-hydroxybenzoic acid and formaldehyde. these calixarenes are characterised by meltingpoint, uv, ir, 1h nm...
Acid ionization in aprotic media is studied using Molecular Dynamics techniques. In particular, models for HCl ionization in acetonitrile and dimethylsulfoxide are investigated. The proton is treated quantum mechanically using Feynman path integral methods and the remaining molecules are treated classically. Quantum effects are shown to be essential for the proper treatment of the ionization. T...
Electrospray-assisted laser desorption ionization (ELDI) is a technique which combines laser desorption with subsequent electrospray ionization. It is useful for directly detecting small and large molecules in solid or liquid samples under ambient conditions. In this paper, the detection of the protein molecules desorbed on a dry protein spot by using pulse laser energies of up to 300 microJ wa...
We analyze extant data of Al, Al and other low ions with the aim of studying the ionization properties of Damped Lyα systems (DLAs) from the analysis of the ratio R(Al/Al) ≡ N(Al)/N(Al). We find good correlations logN(Al) logN(Si) and logN(Al) logN(Fe) that we use to indirectly estimate N(Al) from N(Si) and/or N(Fe) measurements. In this way we determine the ratio R(Al/Al) for a sample of 20 DL...
Most of the benefic effects of negative air ions (NAI) quoted in the literature until the end of the 20 century were obtained with high doses of NAI, but at these doses a phased action was noted: favorable at the beginning, then unfavorable on extended exposures. In Romania, experimental studies on animal or human subjects were made mostly with moderate doses of air ions, close to those in the ...
We study the 3-D hydrodynamic interaction of supernova shock fronts with interstellar clouds to investigate the evolution, the morphology and the deviations from equilibrium of ionization. To this end, we use the FLASH code including PARAMESH, an advanced and versatile parallel adaptive mesh refinement package. We present here the preliminary results obtained modeling a representative case of a...
We show through simulation that quantum interference in nonsequential double ionization can be used to control the recollision excitation with subsequent ionization (RESI) mechanism. This includes the shape, localization, and symmetry of RESI electron-momentum distributions, which may be shifted from a correlated to an anticorrelated distribution or vice versa, far below the direct ionization t...
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